On the Voice Sample page, you can use your device to capture a voice sample. Click Capture with Device -> Record. Ensure the speaker speaks slowly and clearly into your device for about 20-30 seconds. Make sure you are in a quiet place when recording the sample. When you are finished speaking be sure to press the Stop button. If you do not know what to say you can use the follow script-
"Hello I am creating a voice sample for the Remortal app. The last days of the week are Saturday and Sunday. The seasons of the year are winter, spring, summer and fall. Swimming from the Pacific ocean to the Atlantic ocean would require you to go around South America, through the Arctic Ocean or through a canal"